Study On Absorption-transmission-integrated Metamaterial Absorbers

Compared with traditional absorbers,metamaterial absorbers possess a number of advantages,such as efficient absorption,thin thickness,broad and tunable absorption band.Therefore,metamaterial absorbers have been attracting much more attention owing to their extensive application prospects.Here,we mainly focus on the study of a novel kind of absorption-transmission-integrated devices,and the contents of the study are as follows:(1)An ultra-thin and flexible dual-band absorber with a transmission window is designed and experimentally verified.The top layer of the proposed absorber consists of periodically arranged circular and cross-shaped units.The middle layer is a dielectric spacer,and the bottom layer is a band-pass FSS(Frequency selective surface,FSS).The experimental results indicate that efficient absorption is achieved at 5.92 GHz and 17.8 GHz with an absorption of 97% and 95%,respectively.The transmission is above 97% at 12.6 GHz,demonstrating a low insertion loss of 0.14 dB.In addition,the total thickness of the absorber is only 0.288 mm.Due to the ultra-thin thickness and flexible property,the proposed absorber is applicable for some targets with curved surface.(2)A dual-band absorber with polarization-dependent transmission windows is designed.The absorber consists of periodically arranged double-square resonator at the top layer,the dielectric in the middle layer and band-pass FSS at the bottom layer.Full-wave simulation results show that the absorption is more than 96% at both 8.9 GHz and 15.8 GHz.The transmission of TE wave is above 96% at 11.68 GHz,and the transmission of TM wave is up to 95% at 12.8 GHz.Since the transmission window of the absorber is related to the polarization of the incident wave,it has potential application in communication.(3)A transmission-type absorbing device is designed,which not only provides the broadband radar absorption and low infrared emissivity but also possesses a transmission window.It consists of three functional layers,including an infrared low-emissivity layer,a radar absorption layer,and a band-pass FSS layer.Full-wave simulation results show that the absorption efficiency is higher than 90% in the range of 8.16 GHz-19.34 GHz.A transmission window appears at 2.68 GHz with a transmission efficiency of 80%.The infrared emissivity is less than 0.3.This device has a transmission window for communication,and also has a radarinfrared compatible multispectral stealth function,which makes it has potential application in the next generation of high-performance radome.